In a coil,the current changes from $-2 \,A$ to $+2 \,A$ in $0.2 \,s$ and induces an emf of $0.1 \,V$. The self-inductance of the coil is: (in $\,mH$)

The self-inductance of a solenoid is:

Two coils have self-inductance $L_1$ and $L_2$. The current through them is increasing at a constant rate. If the power dissipated in both the coils is the same, then the ratio of energy stored in the coil having inductance $L_1$ to that in $L_2$ is

For a solenoid,keeping the turn density constant,if its length is halved and its cross-sectional radius is doubled,then the inductance of the solenoid increases by.....$\%$

$A$ magnetic flux of $5 \mu Wb$ is linked with a coil when a current of $1 \ mA$ flows through it. Calculate the self inductance of the coil.

$A$ wire in the form of a tightly wound solenoid is connected to a $DC$ source and carries a current. If the coil is stretched so that there are gaps between successive elements of the spiral coil,will the current increase or decrease? Explain.